| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.46 | 0.48 | 0.44 |
| 2024 | 0.53 | 0.59 | 0.45 |
| 2023 | 0.66 | 0.8 | 0.49 |
| 2022 | 0.68 | 0.76 | 0.59 |
| 2021 | 0.82 | 0.94 | 0.74 |
| 2020 | 0.88 | 1.01 | 0.75 |
| 2019 | 1 | 1.16 | 0.93 |
| 2018 | 1.22 | 1.42 | 0.95 |
| 2017 | 1.38 | 1.61 | 1.22 |
| 2016 | 1.72 | 2.14 | 1.53 |
| 2015 | 2.17 | 3.12 | 1.61 |
| 2014 | 1.79 | 2.26 | 1.31 |
| 2013 | 3.04 | 5.43 | 1.97 |
| 2012 | 5.92 | 8.75 | 3.87 |
| 2011 | 9.59 | 11.74 | 7.99 |
| 2010 | 11.55 | 15.7 | 8.72 |
| 2009 | 8.07 | 12.23 | 5.44 |
| 2008 | 9.13 | 17.42 | 4.97 |
| 2007 | 11.11 | 15.39 | 8.24 |
| 2006 | 6.21 | 10.46 | 3.07 |
| 2005 | 1.3 | 3.28 | 0.64 |
| 2004 | 0.56 | 0.68 | 0.37 |
| 2003 | 0.43 | 0.52 | 0.34 |
| 2002 | 0.47 | 0.6 | 0.36 |
| 2001 | 0.64 | 1 | 0.3 |
| 2000 | 0.49 | 0.63 | 0.35 |
| 1999 | 0.47 | 0.77 | 0.37 |
| 1998 | 0.46 | 0.59 | 0.25 |